On Wed, Sep 19, 2007 at 03:03:51AM +1000, Anthony Towns wrote: > > > > Heedless of the effect on the DNS round-robin functionality I describe > > above, the authors of RFC3484 specified (s6 rule 9) that all addresses > > should be sorted by "proximity" to the host making the choice - where > > "proximity" is defined as the length of the common initial address > > prefix. > > So if getaddrinfo() has always behaved in this way, I don't see a great > deal of justification in changing it. The bug log indicated that there > were pre-rfc implementations of getaddrinfo() that behaved more like > gethostbyname() at least wrt round-robin DNS; but I've got no way of > verifying that.
glibc is the only implementation I know of that does this. I've attached a small test program. The results are: sarge: libc6 2.3.2.ds1-22sarge5: random order etch: libc6 2.3.6.ds1-13etch2: ordered results On other implementations I'm aware of is in libbind. You'll need to run configure with the --enable-libbind for that. It doesn't reorder it. I don't know of any of the other libcs in debian actually provide getaddrinfo(), but I doubt they'll reorder. There are also lots of applications that have a wrapper around gethostbyname() in case the libc doesn't provide it. It's highly unlikely any of those will do any reordering. > > This may have been a disputed but arguable definition of real network > > proximity for IPv6 in at the time 3484 was written. But it is clear > > now that it is not such a measure in the real IPv6 internet, and it > > has never been such a measure in the IPv4 internet. > > I hadn't seen any indication it was disputed for IPv6 prior to your mail. > The patch in glibc only affected IPv4 addresses, for that matter. I've also stated that it might not work properly for IPv6. It's likely that something in the same /32 is close network wise, it's even more likely for /48 and /64, but you probably don't want to go below the /32. Kurt -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]